Dentists use high speed turbines in dental handpieces to rotate dental burrs at high speeds (i.e. in excess of 100,000 rpm). To enable the drill to be rotated at such high speeds, the drill bit is held by bearings and a turbine in the head of the handpiece. Air is forced into the head of the handpiece to rotate the turbine, which in turn rotates the drill bit. The air is then exhausted out the back of the handpiece.
When the handpiece is used, the head of the handpiece, which is inserted in the patient's mouth, becomes contaminated. The handpiece must thus be cleaned and sterilized between uses. The most effective way to fully sterilize the hand piece is to autoclave it. However, the heat from the autoclave can, over time, damage the turbine bearings. Once the bearings have been damaged, the high speed handpiece cannot be effectively run at the necessary speeds to be used as a drill. Further, grit can sometimes get into the handpiece. This grit can sometimes be removed by ultrasonically cleaning the handpiece. However, ultrasonic cleaning will also damage the bearings. Proper cleaning and sterilizing of the handpiece will thus effectively shorten the life of the high speed handpiece. High speed handpieces are very expensive. Thus, to prevent the possibility of shortening the useful life of the handpiece, some dentists resort to merely wiping down the outside of the handpiece. This may clean off the contaminants on the outside of the handpiece, but it cannot not properly disinfect the exterior of the handpiece, and does not clean or disinfect the interior of the handpiece. Grit which may accumulate in the handpiece will therefore remain in the handpiece unless the handpiece is opened and manually cleaned.
To overcome this problem, some manufacturers have introduced fully disposable high speed handpieces. One such handpiece was produced by OralSafe, of Temecula, Calif. Another is shown in U.S. Pat. No. 4,842,516, to Choisser. Although fully disposable handpieces overcome the problems associated with the inability to fully clean a high speed handpiece without ruining its bearings, they are still expensive.
Currently available high speed handpieces typically include a fiber-optic cable to light the area where the doctor is working in the patient's mouth and a water stream to cool the bit as the dentist performs a drilling operation on the patient's teeth. Typically, the water and light outputs are located on the sleeve of the handpiece, behind the head which carries the turbine. The placement of the light and water outputs can be seen, for example, in U.S. Pat. No. 4,966,552 to Gonser. The light coming from an area behind the head of the handpiece does not adequately light the work area in the patient's mouth. Because the light is rather far from the drill bit, the light becomes diffused because of the longer distance traveled, and thus does a poorer job of lighting the workarea. Further, because the light comes from one direction, rather than all around the drill, it is possible that the light will be totally ineffective for use when the handpiece is used in certain angles. Similarly, with the water exiting the handpiece from the sleeve, the water is not accurately aimed at the drill bit, or may not contact the drill bit. Thus, the drill bit may not be adequately cooled during use.